Abstract
With increasing loading of potassium promoter, Ag/CaCO3 catalysts exhibit a clear maximum in selectivity towards propene epoxide formation. This behavior correlates with changes in silver particle size distribution as revealed by HREM and XPS. Maximum selectivity and activity are achieved when the catalyst contains a large proportion of Ag particles whose size lies in the intermediate range 20-40 nm. Ag particles that are either much smaller or much larger than this are less selective towards epoxidation. The mechanistic implications of these findings are discussed and comparison is made with the corresponding properties of Ag/α-alumina catalysts normally used for ethene epoxidation.
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Zemichael, F.W., Palermo, A., Tikhov, M.S. et al. Propene Epoxidation over K-Promoted Ag/CaCO3 Catalysts: The Effect of Metal Particle Size. Catalysis Letters 80, 93–98 (2002). https://doi.org/10.1023/A:1015484121891
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DOI: https://doi.org/10.1023/A:1015484121891